Field of the Invention
The invention generally relates to wireless communications, and more particularly, to wireless communications devices and related methods for performing positioning measurements in a service network.
Description of the Related Art
In a typical mobile communications environment, user equipment (UE) may communicate voice and/or data signals with one or more service networks via cellular stations of the service networks. The wireless communications between the UE and the service networks may be in compliance with various radio access technologies (RATs), such as the Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA 2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, Universal Mobile Telecommunications System (UMTS) technology and others.
In recent years, there is a growing need for a positioning method to determine the position of a UE for a variety of applications. A Global Positioning System (GPS) based scheme and a terrestrial positioning based scheme are widely known as positioning methods of the UE. The GPS based scheme measures the position of the UE using satellites. However, the GPS based scheme needs to receive signals from at least 4 satellites and cannot be used indoors. Meanwhile, the terrestrial positioning based scheme measures the position of the UE location by using a timing difference between signals received from base stations (BSs) and needs to receive signals from a number of base stations. The terrestrial positioning based scheme estimates the position of the UE mainly using a synchronization signal or a reference signal. Observed Time Difference Of Arrival (OTDOA) is one common positioning technology for such terrestrial positioning based scheme, in which a UE measures the reference signal time differences (RSTDs) between positioning reference signals (PRSs) sent by three or more different base stations or cells to obtain the differences between distances from different base stations to the terminal, so as to achieve the purpose of positioning.
However, a plurality of base stations or cells can participate in determining the position of a UE. In actual implementation, a plurality of stations or cells may periodically transmit positioning signals to a UE during a plurality of respective position occasions and the UE may then estimate and determine a measurement result for each base station based on the received positioning signals. Currently, although multiple positioning signals may be received from each base station during a plurality of position occasions for the UE, only a portion of the received positioning signals or a portion of positioning signals which are received during a portion of the position occasions may be applied to obtain the measurement results for the bases stations, thus making the measurements become incorrect and unreliable.